7.1 Suitable means for detecting the leakage of
gas should be provided in a compartment containing a gas-consuming
appliance or in any adjoining space or compartment into which the
gas, of greater density than air, may seep.
7.2 Gas detectors heads should be securely fixed
in the lower part of the compartment in the vicinity of the gas-consuming
appliance and other space(s) into which gas may seep. In areas where
the detector head is susceptible to damage in the lowest part of the
compartment (e.g. engine space bilge) the detector head should at
least be fitted below the lowest point of ignition.
7.3 A gas detector system of a suitable type should,
preferably, be actuated promptly and automatically by the presence
of a gas concentration in air of not greater than 0.5 per cent (representing
approximately 25 per cent of the lower explosive limit). The detection
system should incorporate a visible and audible alarm, which can be
heard in the space concerned and the control position with the vessel
in operation.
7.4 Gas detection system components (i.e. gas
detector head) likely to be in an explosive air/gas atmosphere should
not be capable of igniting that atmosphere.
7.5 In all cases, the arrangements should be such
that the detection system can be tested frequently whilst the vessel
is in service and should include a test of the detector head operation
as well as the alarm circuit, in accordance with the manufacturer's
instructions.
7.6 The detection equipment should be maintained
in accordance with the manufacturer's requirements.